To The

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Eighth Edition July, 1996

Martin Bodo Author

Harold Moorehead Editor, Photographer

jody Coil Production Manager

janne Masingale Typographer

DEDICATION

To my father, Joseph Bodo, who sparked my interest in electronics at an eadyage.

ABOUT THE AUTHOR

Martin Bodo is the founder and president of Corporate Systems Center.

An avid computer enthusiast since his eady teens, he holds a degree in Physics from the University of Santa Clara.

SPECIAL THANKS To

The entire CSC staff who have helped write, edit, sell, and distribute the Hard Drive Bible to over 40,000 satisfied customers.

ACKNOWLEDGEMENTS

We would like to thank all of the manufacturers who provided us with data for this publication. Without their cooperation, production of this book would not have been possible.

Maxtor Technical Support Department Maxtor Service Center

Quantum Technical Supporlt Department Western Digital Technical Support Department Jim Plelps - Rodime Inc.

Bill Rudock - Seagate Technology Mike Mori - Sycard Technologies

90000

9 780964 150317

International Standard Book Number: 0-9641503-1-X

Copyright © 1989-1996 by Corporate Systems Center. All rights reserved. Printed in the United States of America. Except as permitted under the Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system without the prior written permission of Corporate Systems Center.

Software programs distributed on CD-ROM with this book arc copyrighted by the various authors. All trademarks contained herein arc the property of their respective owners.

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CSC's corporate headquarters is located in Sunnyvale, California. This location puts CSC at the epicenter of the latest developments in data storage technology.

About esc

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was founded in 1986 by our president, Martin Bodo. Since then, we've grown consistently by providing the best customer service in the industry. Our mission is to offer quality data storage products available and to back them up with professional service and support.

Our in-house technical service center provides free lifetime technical

support for hardware customers.

We're proud to employ the most technically qualified individuals in the data storage industry.

Corporate Systems Center proudly services the entire digital data storage market, from manufacturers to end users.

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PCI WIDE SCSI·III CONrROLJtER

UNIVERSAL SCSI CONTROLLER

• ASprM

, DOS, OS/2™, Windows '95 and NfM drivers included

• An ideal match for fast Pentiums and Windows '95

• Supports both Wide and Narrow SCSI drives

• FLASH BIOS option permits upgrade to SCSI·III software features

• Automatic termination eliminates data errors

You asked for it - we built it. The PCI bus is a perfect performance match for Wide SCSI-III. Take advantage of these new standards and get twice the data rates of SCSI-II. Connect up to fifteen Wide drives to your fileserver and get double the performance of standard SCSI-II drives. This card is ideal for disk intensive fileservers and Audio Visual workstations which operate several drives concurrently.

You want maximum system performance with the fewest headaches. Now,existing, inexpensive SCSI-II drives can share the bus with Fast & Wide SCSI-III. Get it all - compatibility, ease of installation, and FastCache ™ performance with Fast & Wide SCSI-III transfer rates.

Drive transfer rate: 20MB/sec; Bus transfer rate: 133MB/sec. Call us today for a free price comparison guide including Fast & Wide SCSI-III hard disk drives and other storage devices.

csc FAsrCACHCM PCMCIA CtJ~NrROLLER

esc's

fASTCACHr PCItIC'A SCS'-II

• Fastest PCMCIA controller available

• ASprM

Compliant. CD·ROM and hard disk drivers included

• 3.3MB/sec Sustained Data Transfer Rate; 10MB/sec Burst Rate

• Full, high performance Windows '95 and OS/2 WarpTM drivers are included

• Supports Windows 3.x, Windows for Workgroups, DOS, and OS/2

• Includes Cable and Software - Compare and Save

Upgrade your notebook to Fast SCSI-II. The CSC FastCache^MPC Card slips into your PCMCIA slot and brings your notebook all the power of CD-ROM, DAT, optical, and Fast SCSI-II hard drives. This controller is ASPI compliant and includes free CD-ROM and hard disk drivers.

Using PCMCIA is the only way to add CD-ROM with acceptable performance. The PCMCIA Fastcache Card is fully format compatible with most other SCSI cards, so you can share peripherals with your desktop. Made in the U.S.A.

Call today and connect any SCSI device to your notebook.

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CSC llJSTCACHr x J 0 FLOPPY

ADVANCED 'EArURES

• Accelerates lfloppy performance up to 1 0 times

• Transfers data instantly using 1.5MB cache

• Duplicates disks in less ,than 15 seconds

• Complete ki11 includes drive and controller

• Now includes motorized disk eject

You purchased high end Pentium performance. The video and SCSI accelerators work great. But you could die frustrated waiting for the floppy drive.

Slip the new lrastCache XIO into your system and hold on. A separate microprocessor and 1.5MB RAM cache now control your floppy. You can boot faster from a floppy than from a hard drive. Your floppy drive is finally useful.

Transfer data instantly. Duplicate disks in seconds, not minutes. Install large applications instantly. The

esc

FastCache X10 runs applications up to 10 times faster than normal drives.

The FastCache X10 is designed for people who can't afford to wait. Try it risk free for 15 days. Call us today.

AK47 ISA SCSI .. II CONTROLLER

ADVANCED FEATURES

• True FAST SCSI-1110MB/sec burst transfer rate

• Sustained transfer rates reach 3-4MB/sec - depending on processor and ISA : bus speeds

• On board floppy controller supports 4 drives, including 2.88MB units and

"fast floppy tapes"

• Includes floPI)Y cables, internal SCSI coble, update and ASPI, Windows '95 and Windows NTM driver software

• Easy plug and play installation in any standard 16 bit slot

• Free softwarEl upgrades from the CSC BBS

Connect any IBM compatible system to the world of CD-ROM and Fast SCSI-II drives. You'll get maximum SCSI disk system performance without headaches. CSC's proprietary "hyper-FIFO" design and industry standard drivers make this card compatible where others fail.

Strong termination and power protection eliminate cabling problems and offer maximum reliability, even with up to 7 drives attached. The optional caching drivers accelerate CD-ROM performance to hard disk speeds.

Flash BIOS lets you add additional SCSI features with free software updates from the CSC BBS.

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UNIVERSAL DRIVE DUPLICA1'OR

COPIES TO AND fROM ANY DRIVE:

• SCSI-I, SCSI-II, or SCSI-III disk drives

• CD-ROM players and CD-R recorders

• Erasable Optical Cartridges

• DOS and 32 bit NT compatible files, even on file servers

• IDE, MFM, Rll, or ESDI drives

• Now supports SCSI tape drives

Easily copy an entire hard drive or CD-ROM. Using standard drives, you can instantly copy an entire disk, including operating systems, directories, files, simply ... everything. Make fast backup copies of CD-ROM software using CD-R drives. Instantly format drives for PCs, Sun, SGI, and UNIX workstations.

Dealers and system builders can save hours of time by preinstalling software on one drive and then using that drive as a master for rapid duplication. Users can back up and restore data from CD disk, MlO optical disks, or even DOS compatible files.

CSC's new menu driven duplication software saves MIS profeSSionals hours every day. Fully install standard configurations over a network using the DOS file compatibility mode to create master image files on your server.

Any data is fair game for the FastCache duplicator. Data is precisely duplicated on a byte by byte basis.

Exact copies result.

WINDOWS 195 TAPE BACK I'P

MAXIMIZE YOUR SCSI PERfORMANCE

• Universal SCSI device support including 4mm, OAT, 8mm, Exabyte, WI', DLT, autoloaders and others not supported under Microsoft backup

• Easy to use - Fast menu driven interface shows files on disk and tape

• Automatic selection of files which require backup

• True 32 bit performance and reliability

You made the right choice with Windows '95. Now get powerful multitasking tape backup and restore protection. FastCacheM backup is your high performance backup and restore solution. Get full compatibility with SCSI devices not supported by Microsoft BackupfM. Protect your data from accidental deletion and system crashes with fast, efficient backups.

Installation is automatic. Backup operation has never been simpler. A clean graphical user interface shows files on tape and disk for easy selection.

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SCSI ~VlECHANICM FOR WINDOWS 195 AND NT

IIIIAX,.,ZI' YOUIl ICSI I""fOUlAIIC'

• low level format drives, optical cartridges & tapes - reassign defective sectors manually or automatically

• Verify drive Ilerformance and data integrity

• Clone drives - including Windows '95 and NT operating systems

• Read manufclcturers' information and mode settings

• Easily changE~ drive modes and cache settings

Windows '95 and NT are great operating systems. But it's tough to manage servers and workstations without good SCSI utilities. Get the new Windows '95 SCSI utility pack from

esc.

All the features Microsoft left out are now yours.

Control disk drive "mode pages" to increase efficiency and change cache parameters.

Read the manufacturers' information and mode settings. Verify drive performance and data

integrity with efficient surface scans. Clone entire hard drives - including Windows '95 and NT operating systems and files. Automatically reassign bad sectors for data security.

This true 32 bit software is designed specifically for Windows '95 and NT. Call CSC today and maximize your Windows '95 SCSI performance.

CD-ROM DUPLICATOR

QUICKLY COPY CD-'O.S

• Sustained reading speed 4X - 600KB/sec

• Sustained writing speed 4X - 600KB/sec

• Both drives operate concurrently for top performance

• System includes controller, drives, software and blank disk

• PCI controller, cables and terminator me included

Use your PC to copy CD-ROM disks in minutes. Make software backups on rugged, permanent media. Produce disks quickly and economically for distribution. No mastering software or multimedia experience is required.

Everything you need is included. You get a complete external system with two matched drives: a 4X!6x CD-ROM reader/writer and an NY certified 700MB SCSI drive. The CSC FastCache duplication software and controller take advantage of both, operating them Simultaneously to automatically duplicate disks in minutes. You can even transfer CD images to and from hard disks or optical cartridges.

Plug the controller card in any Pentium PCI slot, connect the external unit, and you'll be up and running out of the box. Software and hardware are matched for compatibility and top performance.

•

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DISK ARRAY ENCLOSURES

SCSI SERVER TOWER

• Holds up to 8 SCSI drives

• Solid steel case with dual cooling fans and microfiltering

• Ideal for LAN servers

• Up to 2 SCSI ports and up to 8 ID switches, optional

• Holds any combination of half or full height 5.25" drives

• Custom cobling to meet your specifications

CSC is now delivering the ultimate SCSI enclosure. Up to eight half height SCSI hard, CD-ROM, optical, and tape drives can be configured to your specifications.

Whether you need a network storage subsystem, an external SCSI drive case, or a

full-blown disk array, CSC has it. We'll custom build it complete with the drives of your choice for free, when drives and tower are purchased together.

A professionally designed micro-filtered air cooling system featuring dual forced air fans protects sensitive optical and tape drives.

CD-ROM rOWERS

NETWORK CD TOWER

• Access data immediately with seven drives on line simultaneously

• Ideal for Novell, OS/2, Banyan, and NT network servers

• Includes dual cooling fans for long term reliability

• Full SCSI-II command set for software compatibility

• Heavy duty enclosure and 300 watt power supply

You demand top network performance. Don't even think of using CD changers on a network. With a heavy load of multiple users, changer performance is just too low.

A heavy duty network CD-ROM tower from CSC is your solution. With seven drives on line simultaneously, your workstations will access data immediately. The custom manufactured, solid steel disk array enclosure with microfiltered fans ensures long term, reliable operation. This system is chosen by government, military, and educational institutions.

Call today for your complete seven drive subsystem, ready to plug and play on your file server.

Custom configurations are also available.

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Corporate Systems Center (408) 743·8787

SCA Hot Pl.ugs ... o • • • o • • • • • • • • • Il • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 4 7 PCI Interface ... , ... 49

Choosing a Hard Drive and Controller ... 51

Controller Setup and Jumpering ... 55

ISA Bus Basc~ I/O Address ... 55

ISA Bus Base BIOS Address ... 56

ISA Bus DMA Channel ... 56

ISA Bus Controller Interrupt."... . 56

Floppy Address ... " ... 56

A Tip for Motherboards with G'Extended Chipset" Setup ... 57

Drive Setu ^1[>and J um pering ... 59

Typical IDE Drive Installation ... 59

IDE Drive ]llmpering ... 60

DSO or DS 1 Confusion ... 60

MFM, RLL and ESDI Drive ]umpering ... 60

SCSI Drive ]llmpering ... 61

"Drive Cab lJlng ... e _ . . . (J • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 63 IDE Drive Cabling ... 63

What are thtese Twisted Cables? ... 63

Single Drives (MFM,RLL or ESDI) Cables ... 64

Multi DriveMFM and RLL Cabling ... 64

l'ermination ... 64

.Multi Drive ESDI Cabling ... 65

SCSI Drive <:abling ... 65

SCSI Cable Identification ... " ... 67

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Drive Jumpers ... ^c• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 211 Atashi 3085 ... " ... 211

CDC Wren III Series ... 212

CDC Wren III Series (SCSI ]umpers) ... 212

CDC Wren III Series (ESDE & SCSI) ... 212

CDC Wren V Series ... 212

Conner ... 221

Digitals DSP Series ... 230

Fujitsu ... 231

Hitachi ... 234

Hewlett Packard ... 236

IBM ... 239

Maxtor ... 249

Micropolis ... 256

Quantum ... 258

Seagate ... 267

Western Digital ... 277

CD-ROM ... 279

CD-Media ... 279

CD-ROM Drive Operation ... 280

CD-ROM Standards ... 280

ISO 9660 ... 280

Mode 1 ... ,281

Mode 2 ... ,281

CD-ROM XA ... 281

X Hard Drive Bible © csc 1996

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Floppy Drlves ... 4J • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 287 Industry Standard Floppy Drives ... " ... 287

I{loptical Drives ... 287

Zip Drives ... " ... 287

Accellerated Floppy Drives ... " ... 288

I{loppy Driv"e List ... 288

Optical Disk Drive Technology ... u • • • • • • • • • • • • • • • • • • • , • • • • • • • • • • • • • • • • • • • • • • • • • 289 CD-ROM Drives ... " ... 289

WORM Dri'res ... 289

I~rasable Op,tical Drives ... " ... 291

I)~ and H1DCD ... ' ... " ... 291

D~'s Competitor is High Density Compact Disk (fIDCD) ... 291

Optical Dis1, Capacity ... 292

Erasable Drive Capacities ... 292

WORM lDrive Capacities ... 292

Optical Ju)teboxes ... o • • • • • • • • • I, ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 293 Optical DrIve Specificatio:tls ... $ . . . 295

Optical Drive List ... " ... 295

Tape Driv{~s ... ' ... 303

Tape Drive Interfaces." ... 303

Floppyl:ape ... " ... 303

Pertec ... 303

QI(:-02 ... " ... 304

QI(:-36 ... " ... 304

SCSI ... 304

ESCON ... , ... 304

FIREWIlrn ... 304

Data Compression & Honest Capacity ... 304

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esc

Benchmark TestS ... f)311l Softw'are ... 313

Disclaimer ... · ... 313

Copyright Notice ... 314

System Notes ... o • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 329 Industry- phone List ... . ~ ... 333

BBS Numbers ...•... 367

Directory-... 371

I Glossary-... t • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 377 Index ... 42].

XII Hard Drive Bible @ CSC 1996

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HISTORY OF DISK DRIVES

T

he magnetic recording technology used in today's disk drives can be traced back to around 500 B. C. when the mineral magnetite was discovered. Magnetite is the naturally occuring magnetic material that was first used in compasses. Alchemists in the first century B.C.

discovered the first magnetic compasses when they noticed that load- stones hung from a string always pointed the same way.

Several hundred years later, the connection between electricity and magnetism was discovered. Early scientists noticed a that a com- pass needl<:~ was deflected when it was put near a wire carrying electric current. It was in this era that magnetic technology was pioneered by experimental geniuses like Danish physicist Hans Christian Oersted and English scientist Michael Faraday who discovered the principles of electromagnetic induction.

The first practical lnagnetic recording device was the Telegraphone patented in 1898 by Danish telephone engineer and inventor Vlademar Poulsen. The Telegraphone was a crude audio recorder using a stretched magnetized wire. The Telegraphone attract- ed considerable curiosity when it was first exhibited at the Exposition Universelle in Paris in 1900. The few words that the Austrian emperor Franz Josef spoke into it at that exhibition are believed to be the ear- liest survivilng magnetic recording.

As World War I approached, the German war effort assumed lead- ership in nlagnetic r(~cording technology. The German firm AEG was the first to use plastic strips (tape) for magnetic recording. The Germans put magnetic recording to its first military application on submarines:. Secret communications were recorded on crude reel to reel tape r(~corders at slow speeds. The tapes were then played back and retransmitted at high speeds to prevent Allied interception. The receiving station used another tape recorder to reconstruct the mes-

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Magnetophon Recorder

2 Hard Drive Bible

sages. By World War II the Germans had perfected the recording technology and manufactured high quality reel-to-reel tape recorders called Magnetophons. These tape recorders were nearly identical to today's high quality audio tape recorders.

In 1945 an American Signal Corps soldier, John T. Mullin, sent two of these captured machines home to San Francisco. The analysis of these units by American engineers at Ampex Corporation in Redwood City lead to the developrnent of the Ampex Model 200 in 1948. The Model 200 was the first magnetic recorder to be manufactured in volume and used commercially. The American Broadcasting Corporation had provided some of the financing for the Ampex recorder project, and was the first to use them in broadcasting the Bing Crosby Show in 1948.

This same technology is

;used in today's high reso- lution audio, video and digital tape drives.

Reel to reel tape recorders and Hollerith punch cards were the main storage devices used in early computers. Paper Holerith cards and paper tapes were used to perform initial program loading when early computers were first powered up. Paper tapes were popularized by the Teletype Corporation who added paper tape readers and punches to many of their Teletype terminals. Paper tape remained popular for over 20 years, lasting until the' early 1970's. It took the convenience and erasability of floppy disks to eliminate paper tapes.

In 1952, IBM, realizing the need for a random access method of data retrieval with faster access than magnetic tapes, sent Reynold B.

Johnson to San Jose, California to head hlp a magnetic recording research team. Johnson 'was convinced that a disk based system was the way to go, but other engineers advised: him to abandon the project. Following his intuition, Johnson designed the first commercially successful digital disk drilve. In 1956, IBM announced the Model 350 RAMAC (Random Access Method of Accounting and Control). It was a quantum leap in disk technology for its time. The RAMAC stored 5 megabytes of data on fifty 24-inch disks, spinning at 1200 RPM, and had an access time of 600 milliseconds. The resulting data transf(~r

rate was .10 Mbits per second. Compare that to the 25 to 80Mbits per second data rates typical today! The popular name for this huge stack of disks at IBM was the "baloney slicer".

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Corporate S,stems Center (408) 743·8787

In 1955, realizing that magnetic recording density was severely lim- ited by the: number of linear stripes (tracks) on the tape, two brilliant engineers at Ampex Corporation, Charles Ginsburg and Ray Dolby, developed the helical scan recording system. Their ingenious scan- ning system uses a tiny spinning magnetic hea,d with tape wrapped around it in a spiral. This design

packed recording tracks much m.ore tightly onto the tape than was previously possible. The helical scan recording tech- nique provides an extremely high recording density with a single small head. Helical scan recording its now used in every video recorder (VCR), Digital Audio Tape drives (DATs), and all high capacity tape backup drives. I have read with respect several documents authored by Ginsburg and Dolby at Ampex. These engi-

neers deserve more credit for their brilliant invention of the mechanisms and recording techniques copied in every modern VCR.

In 1961l, IBM pushed disk data storage ahead by announcing the 1301 Disk Storage unit that used aerodynamically shaped recording heads that "flew" above the surfaces of the spinning disks. This enabled roughly 10 times as much information to be packed in each square inch of disk surface. This head design would eventually become the "Winchester disk drive".

The next year, IBM announced the 1311 Disk Pack unit which helped speed the end of th(~ punched card era by providing removable and interchangeable "disk packs" containing six disks protected by a transparent plastic "cake cover." Each disk pack could store roughly as much data as 25,000 punched cards. Magnetic disks were finally becoming a practical storage medium for computers.

During 1964, flly parents made the mistake of conceiving Martin Bodo. Little did they know how much trouble I would eventually cause theDa. My early fascination with computers would ultimately place Corporate Systems Center (CSC) at the forefront of magnetic data storage technology.

In 1967, IBM assigned David L. Noble to head a research team to develop a convenient storage medium to store and ship microcode. In

The Baloney Slicer!

Hard Drive Bible 3

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IBM 33FD Floppy Drive

1969 several engineers l{~ft the project to join Memorex. Memorex soon became an industry leader in magnetic media technologies, disk drive manufacturing, and magnetic media production.

In 1970, IBM announced the 3330 Disk Storage Facility which was the first disk storage product to use an electrical feedback system called a "track-following servo" to control a "voice coil" motor that could quickly position recording heads at desired positions over the disk. This combination provided better response time, higher track density, and more reliable operation than was previously attainable.

Twenty years ahead of its time, this closed loop track following servo technology would eventually be used in every large capacity disk drive.

In 1971, the first"disk{~tte"was produced 'by IBM as an ICPL (Initial Control Program Load) d{~vice. It was called the Minnow and was an 8-inch read-only model that stored 81,664 bytes. It caused paper tapes to become obsolete almost overnight.

While IBM and others were developing disk technology at honle in America, Japanese companies like Sony and Japan Victor Corporation aVC) were making rapid advances in consumer VCR technology. By the early 1980's, the Japanese had a lead in helical scan tape drive manufacturing technology that the US could never overcome.

In 1973, the first read-write floppy disk, the Igar (IBM 33FD), which stored an incredible (for it's time) 242,944 bytes - started ship- ping to customers. The original code name of the read-write disk was Figaro, but the initial f and final 0 were removed as a symbolic removal of "fat" and "overhead". IV[emorex was the first company after IBM to produce floppy disk products and soon became a strong competitor in this field.

Also in 1973, IBM announced the 3340 Disk Storage Unit, which featured an ultra light-weight recording head that could "land" on and

"take off' from a lubricated disk while it was still spinning. This eliminated the need for a mechanism to raise the heads off the disk surface before stopping; sub- stantially reducing the cost of manufacturing. The 3340 also contained two spin- dles, each with a storage capacity of 30 million characters. Referring to this arrangement as

a

"30-30", engineers were reminded of th~ famous rifle and called their creation a; "Winchester" file. This term became an industry standard to

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identify this "floating head" design.

In 1975, IBM announced the 3350 Direct Access Storage Device, which marked an extension of Winchester technology and a return from the re:movable disk pack to fixed disks, permitting higher recording densities and lower cost per bit for on-line storage. The 3350 could store data at a density of more than 3 million bits per square inch, an increase of more than 1500 times the density of the RAMAC.

By this tirne, cOITtpetitors were catching up. Several companies, including Shugart, Magnetic Peripherals Incorporated, and PerSci were about to introduce competitive floppy disk drives.

In 1976, the success of the 33FD floppy disk led to the develop- ment of the 43FD using a dual-head drive, that could store 568,320 bytes. This was followed a year later by the double-density, double- sided, 53FD using MFM encoding and a capacity of 1,212,416 bytes.

By 1977, niineteen companies were manufacturing floppy disk drives in the United States and MFM had become the encoding method of choice.

In 1979 Seagat(~ Technology was founded and was the first company to mass produce an affordable hard disk drive (the 5 Megabyte ST506). Seagate has become the largest independent manufacturer of hard drives, having shipped over 50 million units to date.

I was a runny-nosed high school sophomore in 1979. While IBM was inventing thin-film recording heads, I was content with my first 5.25" 160K floppy drive. I was hooked, but I didn't know it.

The data storage industry exploded in the eady 1980's with the help of brilliant engineers who had business sense. Alan Shugart made the floppy disk the standard for data interchange and floppy drive sales soared. By 1982, hard disk drive sales had exploded and form factors were shrinking frotn 14" disks to 8" disks. The 5.25" form factor made popular by Seagate's ST506 was now an industry standard.

When I graduated from college in 1986, I made a living by modify- ing Alan Shugart's Model 712, 5.25" 10 megabyte hard drives so they would hold 20MB. I was starting to understand the equation for success in the hard drive industry. ^Itwas simple: "Provide the Most Megs in the Smallest Size for the Least Bucks". I saw an opportunity for a company that would initially provide repair services for disk drives.

CSC was born in 1986.

In 1989, IBM announced the 3390 Direct Access Storage Device, which could store as much as 21.5 billion characters in each storage unit -- the same capacity as its predecessor, the 3380 Model K, but at an increasf~d density that required only one-third the floor space.

Gosh, it w(~ighed only 800 pounds!

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Early Conner IDE Drive

6 Hard Drive Bible

As sales of Apple Conlputer's Macintosh line of personal conlput- ers began to grow, the industry was introduced to the idea of using the Small Computer Systems Interface (SCSI) as a standard port for desktop PC peripherals. SCSI at this point wasbasically a glorified 8 bit parallel port. But SCSI vl0uld eventually grow into one of the most popular standards for both low performance PC and higher performance workstation disk drives! Like the IBM-PC, SCSI caught on like crazy because it was hardware with software standards included.

In 1990, Conner Peripherals in partnership with Compaq conlput- ers created and made popular both the IDE interface and the 3.5" hard drive form factor. An enormous volume market for IDE drives grew in the next few years as IB~[ compatible desktop systems grew in popu- larity.

By 1990, there was not one American company left producing helical scan tape recording mechanisms. The Japanese con- quest in consumer electronics was about to payoff.

Soon, all helical scan digital tape recording mechanisms for computer technology would come from Asia. In addition, the American loss of consumer audio manufacturing technology would cost US companies dearly. All digital CD-RO~[ disk drives based on this technology would now come from Japan and the Orient.

In 1991, we designed our first caching disk controllers at

esc.

These cards would eventually sell by the thousands, as the size of CSC continued to double yearly.

In 1991, IBM created another first in drive technology, the MR head. IBM's 9340 drive be:came the first IBM disk to use magneto-resis- tive recording-head technology, and IBM could now boast of bit densities of > 100Mbits per square inch.

In 1992, improvements in mechanical alignment and media boost- ed the capacity of standard diskettes to 2.88MB and "ZIP" diskettes to 100MB. Maxtor Corporation announced the "Magic" MXT series of disk 3.5" disk drives with capacities over 1 GB and access times under 8ms. 5.25" disk drives wlere available in 1994 with over 8GB of for- matted capacity.

As we write the update to the Hard Drive Bible, it is now 1996. It's

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hard to predict the future, but I'll be glad to share a few thoughts on the data storage industry.

Compaq will soon ship Floptical drives with 120 MB capacity in a standard 3.5" form factor. I'm not sure what industry standards will develop, but other than "floptical" drives, I don't see much future for the floppy disk industry. Read the chapter on CD-ROM for more insight. CD-ROM and recordable CD-R drives revolutionizing software distribution.

The hard disk industry, on the other hand, is moving faster than ever. Volunnes are huge while only a few manufacturing companies are staying profitable because of the intense competition. Technology is advancing faster than ever. My friends and I used to talk about "mini- mono" disk heads. Then it was "micro-sliders" and even "nano-sliders".

Today we had a nerd's lunch and talked about "pico-sliders" that fly at 4 millionths of an inch above the disk. As far as I'm concerned, that should be called "contact recording"!

Will hard drive sales continue to grow? To be honest, there are some potential challengers for hard drives. Optical, and Flash technologies are improving. You can bet our friends at Intel hope Flash will kill ha:rd drives. But our friends in Japan working on DVD optical disk drives feel that optical drives will win out in the long run. My opinion is unchanged. For the last ten years, I've had people tell me that something better will replace hard drives. Every time there's a technical advance in Flash or optical drive, there's a corresponding advance in magnetic disk drive technology. Hard drives are here to stay. As magnetic, optical, and semiconductor technologies advance together, hard drives continue to offer more storage for less money, with a better access time. Each technology has it's distinct advan- tages, but the magnetic recording technology used in hard drives is simple, mature and easy to manufacture. Hard drives will remain practical for several more years at least.

In 1996, a major disk drive merger took place between Seagate and Conner Peripherals. I take my hat off to Alan Shugart, CEO of Seagate TechnologJies for that accomplishment. Seagate has a broad line of products from 8" drives to PCMCIA FLASH memory. They're quick on their feet and poised for the future.

But the majority of disk drive manufacturers continue to loose money! This is the largest potential problem facing the data storage industry: price competition. Severe price competition is forcing many companies to abandon research efforts and concentrate on high vol- U1ne, low-trech products. Only the lean, high tech companies will sur- vive the competition.

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Some feel that magnetic recording technology has begun to give way to optical technologies. I agree that optical technology has now become affordable and reliable enough to replace magnetic drives in some selected applications. In the past few years, optical recording techniques pioneered by the Japanese in consumer products have developed to the point where optical drives are manufactured at rea- sonable costs. Many companies like Hitachi, Sony, Ricoh, and MaxOptix do a brisk business selling fast, reliable, low cost optical drJl- ves. I feel that the cOlnpelling advantage behind optical media is removability. Cartridge hard drives and hard drives with removable HDA's are not as large or convenient as optical media. The market for erasable optical drives VlTill continue to grow, but hard drives will remain the best choice for non-removable applications.

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BASIC DRIVE OPERATION

A

ll disk drives perform three basic functions. They spin, seek, and transfer data. The disks inside a hard drive are mounted and rotat- ed by a motor normally located in the center of the disks called the spindle motor. The read/write heads are held and moved in a head carriage that lLlsually also holds the preamplifier electronics. Disks and heads are stacked vertically on the spindle motor, and the head stack assembly is positioned on-track by a servo system.

Raw read data flows from the preamplifier and is encoded and decoded by the drive electronics. The heads read and write this

"encoded" data to the disks (media). Data encoding and decoding circuitry is designed to pack as much information as possible into the snlallest area. Read/write circuits move the encoded data to and from the magnetic recording heads. When writing, the heads convert the electric currents fro:m read/write circuits into highly concentrated magnetic fields. These magnetic fields are stort::d in miniature magnetic groups called "domains" on the surface of the disk. When reading, the magnetic domains stored on the media are converted into electric currents as the h(~ads pass by a second time, operating in reverse to :read data. The heads convert the changing magnetic fields from the diisk into el<~ctric currents as the read data is recovered.

The sections below describe the operation and purpose of the basic components of a disk drive: the spindle motor, head carriage, the servo system, heads and media, and the data encoding circuitry.

Spindle

Molo,rs

The motor used to rota.te the disks in a drive is called a spindle motor. Disk drives use many different types of spindle motors. The type used determines the spin-up time of the disk and torque as well

~ CSC 1996 Hard Drive Bible 9

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Spindle motor used in high-capacity Maxtor

drives

10 Hard Drive Blbl.

as the heat dissipation inside the drive. A motor with a high start-up torque is necessary since the extremely flat heads and disks used in modern drives tend to stick together when power is removed and the heads land on the disk. At the same time, the spindle motor must operate efficiently with a minimum power consumption. Heat dissipated inside a disk drive causes the mechanical parts in the actuator and disk assembly to expand. Because modern, drives require extremely precise mechanical alignment, it is essential that thermal expansion caused by spindle motor power dissipation be kept to a mininlum.

Some early drive designs 'were plagued with stiction or heat problems caused by inadequate spindle motors. Newer designs have resolved these problems by providing spindle motors with higher start- up torques and lower power consumption. All modern drives use microprocessor controlled spindle motor drive circuitry that uses pulse width modulation to minimize power consumption once the drive reaches operating speed.

In high capacity disk drives the quality of the bearings used in the spindle motor asse:mbly is becoming increasingly important. As the concentric tracks in a drive are pushed closer and closer together in an effort to gain higher storage capacities, spindle bearing "runout"

becomes a consideration. The smallest amount of wobble in a modern disk assembly can throw a head assembly slightly off track, resulting in reduced data integrity. Drive manufacturers have gone to great lengths to find affordable spindle motor bearings that offer the lowest amount of runout while still providing long life.

Early hard drives spun at 60 revolutions per second (3600 RPM) because synchronous motors were used that locked to the 60 Hz AC line frequency. Some neV\Ter designs now offer "fast spin" speeds of up to 8000 RPM. At these higher spin speeds, improved spindle motor bearing quality and balancing is essential. Faster response servo systems are also required to track data at higher spindle speeds.

Head Carriage

The mechanical engineer asked to design a modern head carriage is faced with a difficult task: design a perfectly balanced mechanism to

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hold the heads firrnly and rigidly using existing bearing and actuator technology. And management

wants it for free! The head carriage lnust have the lowest moving mass possible, enabling it to be moved hundreds of time a second.

The head carriage pictured uses a linear actuator. The advantage of this type of actuator is that the heads always stay parallel to the recording track. The disadvantages are more complexity and moving parts (higher cost) and higher mass than a rotary actuator.

The head carriage to the right is typical of a modern rotary actuator.

This actuator system has become standard in modern hard disk drives for two main re~asons. Rotary actuators are cheap and reliable. Typically only two ball bearings are

needed at the top and bottom of the actuator.

Media and Heads

The ultimate linliting factors in the push for higher and higher data densities in today's drives are the heads and media. Hard disk media

,~as originally manufactured by spin depositing iron oxide (rust) par- ticles on lnachined aluminum disks. Modern disks are made of annealed aluminunl that is sputtered and plated with magnetic coatings, then polished and coated with rugged lubricated coatings. Disk media is classified by the amount of magnetic field in Oersteds (Oe) required tOl produce enough magnetic dipole reversals in the disk coating to be detected by a magnetic head. Earlier media was easily magnetized using fields of 600 Oe or less. Newer high density media requires fields of 1800 Oe or more to achieve sufficient magnetic pen- e:tration.

Head technologies have also evolved over the years. As head gaps become snlaller, the size of the magnetic coils used must shrink

Head carriage with linear actuator

Head carriage with rotary actuator

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5.25" Plated media

accordingly. New heads must handle higher write currents and be

Stepper Motor Servo Systems

Voice Co;1 Servo Systems

It's hard to inlagine a lnechanism that can move to any position over

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an inch in less than 1/100th of a second and come to a complete stop with- in 0.000 I" of its target. Modern voice coil actuators are capable of doing this over 1,000,000,000 times.

The voice coil servo system is the key conlponent in all newer high perfonnance disk drives. A voice coil actuator is simply a coil of copper wire attached to the head carriage. This coil is surrounded by high energy permanent magnets that are attached to the HDA base cast- ing. To move the head carriage

and "seek" to a track, the control electronics apply a current to the voice coil. The curf(~nt applied induces a magnetic field in the coil that attracts or repels the stationary permanent magnets. The amount of torque induced to move the head carriage is directly proportional to the amount of current applied to the voice coil.

Many drives use an ASIC control chip in the voice coil servo system that contains a D/ A converter. The output of the D/ A converter usu- ally drives a MOSFET power amplifier that provides the current required by the voice coil. The circuitry that moves the head from track to track is simple compared to the circuitry that decodes the servo information recorded on the drive. In order to control the voice coil, the s{~rvo electronics must know precisely where the head is positioned on the drive. The positioning information fed back to the electronics to control the voice coil positioner is called "servo feedback" . Sev,eral different servo schemes are used to provide position feedback informati.on to the drive electronics and "close" the servo loop.

Some large capacity drives use a "dedicated" voice coil servo feedback systenll. When you see a drive in the drive table with an odd number of read/write heads, it probably uses a dedicated servo system. In a dedicated system, the entire surface of one disk is reserved for use by the servo system. Position information is recorded on the reserved (dedicated) disk so that the drive electronics can determine the exact position and velocity of the head carriage.

Assuming that the head carriage holds the entire head stack rigidly together, the position of the read/write heads will track along with the dedicated servo head. A dedicated servo system offers fast positioning and is simple to design. One of the only disadvantages to this system is that since only one head is used for servo, a dedicated servo system has difficulty compensating for thermal warpage of the head

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HISTORY OF DISK DRIVES

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BASIC DRIVE OPERATION

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Spindle

Media and Heads

Stepper Motor Servo Systems

Voice Co;1 Servo Systems